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41.
Raman spectra of molten NaClO3 and KClO3 and of aqueous solutions of these salts were measured over the frequency interval from 50 to 1200 cm−1|. Infrared emission spectra of the molten chlorates and of chlorate-nitrate mixtures were recorded, and absorption spectra of aqueous sodium and potassium chlorate also were determined. The ν3(e) and ν4(e) modes of ClO−3 were split in the molten salt and aqueous solution spectra, and a single, weak band was observed between ca. 80 and 200 cm− in the Raman spectra of molten NaClO3 and KClO3. 相似文献
42.
T. F. Watson D. Belić P. Y. Convers E. J. Boyd S. A. Brown 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):81-85
Thin films produced by depositing tin clusters with sizes between 5 and 10 nm onto silicon nitride substrates were found to
be
highly coalesced resulting in grains with sizes ~30 nm. Exposing the clusters to nitrogen before they were deposited significantly
reduced the coalescence between them and resulted in granular films where the clusters mostly retained their shape. This is
due to a small
amount of tin nitride forming in the clusters. The coalesced and granular films were used to fabricate tin oxide gas sensors.
This was
done by depositing the two types of films onto silicon nitride chips and then oxidising them by baking at 250 °C for 24 h.
It was found that the sensors composed of uncoalesced clusters were much more sensitive to hydrogen. This was attributed to
the smaller grain size and the larger surface area of the granular films. 相似文献
43.
44.
Defant [5] introduced the local Radon–Nikodym property for duals of locally convex spaces. This is a generalization of Asplund
spaces as defined in Banach space theory. In this paper we generalise Dunford"s Theorem [7] to Banach spaces with Schauder
decompositions and apply this result to spaces of holomorphic functions on balanced domains in a Banach space.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
45.
Several analogues of the 9-phenylthioxanthyl (S-pixyl) photocleavable protecting group have been synthesized, containing substituents on the 9-aryl ring and on the thioxanthyl backbone. Each analogue protected the 5'-hydroxy moiety of thymidine in good to excellent yield. The protected substrates were deprotected in 1:1 water:acetonitrile with irradiation at 300 nm, resulting in recovered thymidine in excellent yield, except for the nitro-substituted analogues which gave substantially lower yields. Substrates with 2,7-dibromo or 3-methoxy substitution on the thioxanthyl backbone were also deprotected efficiently with irradiation at 350 nm. Shorter irradiation times were observed in the less nucleophilic solvent mixture of 1:9 trifluoroethanol:acetonitrile, with no formation of secondary photooxidation products. Photodeprotection with high yields was also achieved in the absence of solvent, with no secondary photoproducts. 相似文献
46.
A novel class of nonlinear optical processes is described in which radiation at the nth harmonic is generated through the use of a (2n+1)-order nonlinearity. Utilizing an odd-order nonlinearity, this process allows for the generation and amplification of both odd- and even-order harmonics in isotropic materials. Additionally, this process can always be phase matched in normal-dispersion materials without the use of birefringence. Experimental results are presented in which conical third-harmonic emission is generated from a sapphire sample. 相似文献
47.
Bennink RS Wong V Marino AM Aronstein DL Boyd RW Stroud CR Lukishova S Gauthier DJ 《Physical review letters》2002,88(11):113901
We have observed transverse pattern formation leading to highly regular structures in both the near and far fields when a near-resonant laser beam propagates without feedback through an atomic sodium vapor. One example is a regular far-field honeycomb pattern, which results from the transformation of the laser beam within the vapor into a stable three-lobed structure with a uniform phase distribution and highly correlated power fluctuations. The predictions of a theoretical model of the filamentation process are in good agreement with these observations. 相似文献
48.
We show that the nonlinear phase shift produced by a ring resonator constructed from a given nonlinear optical material can be greater than the phase shift produced by a single pass through an infinite length of the same material when linear and nonlinear absorption are taken into consideration. The figure of merit (defined by the phase shift times the throughput) also improves for the ring resonator over that of the native nonlinear absorbing material. We finally show that these benefits of using the ring resonator as a nonlinear phase-shifting element can enhance the switching characteristics of a Mach-Zehnder interferometer. 相似文献
49.
Bailey PD Boyd CA Bronk JR Collier ID Meredith D Morgan KM Temple CS 《Angewandte Chemie (International ed. in English)》2000,39(3):505-508
By building key structural features into hydrophilic drugs, they can be recognized by the PepT1 transporter system of the small intestine and rendered orally active. The model shown provides, for the first time, a 3D template for all known substrates of PepT1. 相似文献
50.
Donald B. Boyd David W. Smith James J. P. Stewart Erich Wimmer 《Journal of computational chemistry》1988,9(4):387-398
The monocyclic β-lactam [[4(S)-methyl-2-oxo-1-azetidinyl]thia]acetic acid was studied by the semiempirical molecular orbital methods AM1, MNDO, and MINDO/3. Using the reaction coordinate option in the program MOPAC on VAX and Cray X-MP computers, the potential energy curve was calculated for rotation of the C2-N1-S-C torsional angle in the conformationally flexible side chain while optimizing all other geometrical variables in the molecule. The trajectory taken during geometry optimization was found to be sensitive to the computer, the program version, the convergence criteria, and the degree of code optimization used in the calculation. In order to reduce the likelihood of spurious results, conformational or reaction energy hypersurfaces need to be calculated with the more precise SCF convergence and minimization criteria available in programs for MINDO/3, MNDO, and AM1 calculations. The nitrogen in the model β-lactam antibiotic is predicted to invert periodically as the dihedral angle to the exocyclic N-substituent sweeps through 360°. 相似文献